It is well known in the art that solid marking compositions can be formulated from mixtures of waxes, fatty acids, colorants, and color extenders. These solid marking compositions can be used to fabricate crayons (e.g., by low pressure injection molding or gravity pour molding), which can be used to draw, write, or color on porous and non-porous substrates. Crayons are most often used on various types of paper, such as notebook paper, art paper, and posterboard. Furthermore, crayons are available in a wide selection of colors, ranging from primary colors to fluorescent colors.
A variety of crayons and marking compositions have been disclosed in the patent literature. See, for example, U.S. Pat. Nos. 3,409,574; 3,933,708; 4,212,676; 4,990,013; and 5,383,954. However, these and other conventional approaches for providing crayons and marking compositions have been ill-suited for marking on colored substrates, especially dark substrates. In this respect, upon application to colored substrates, especially dark substrates, crayons and marking compositions of the prior art generate marks that are dull and that are not bright or vivid enough to be readily seen against such dark backgrounds.
Accordingly, it will be appreciated that there exists a need for a marking composition and method that permits the formation of bright and vivid marks on dark substrates. Particularly, there exists a need for a marking composition and method that not only produces bright and vivid marks on dark substrates, but which is also non-toxic, simple to make and use, chemically stable, and capable of generating various colors. It is an object of the present invention to provide a marking composition and method that satisfies these needs. These and other objects and advantages of the present invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.